微量元素（Ti、Zr、C）对核聚变堆钨基材料的强韧化及机理研究

核聚变堆的开发要求面向等离子体钨基材料具有良好的室温韧性、高温强度、高的再结晶温度以及优越的抗辐照性能。然而，纯钨存在低温脆性、再结晶脆性、辐照脆化等缺点。其中，引起钨低温脆性的主要原因是O、C、N等杂质元素偏聚在晶界形成脆化层膜，造成晶界结合强度降低，从而导致晶间脆断。因此，如何调控钨晶界中杂质元素的分布、存在形态，净化与强化晶界，减少间隙杂质原子对晶界的脆化作用，是提高钨基材料力学性能的关键。对此，本项目将采用放电等离子烧结或微波烧结法制备W-Ti-Zr-C系块体合金，研究微量合金元素Zr、Ti等对钨中的O、N、C等间隙杂质原子的分布及存在形态的调控作用，以及对钨基材料力学性能的影响机制，特别关注晶界杂质含量对力学性能的影响规律以及Zr和Ti添加的晶界的净化和强化作用。项目研究成果将为高性能钨基材料的开发提供科学依据。

The development of fusion requires that tungsten-based plasma facing materials (PFM) have high performance, such as high room temperature toughness, high temperature strength, high recrystallization temperature and good irradiation resistance. However, pure tungsten exhibits severe embrittlement in several aspects, including room temperature brittleness, recrystallization brittleness and irradiation-induced brittleness. The low temperature brittleness of tungsten is strongly related to the segregation of trace interstitial impurity elements (O, C, N) on grain boundaries, which forms brittle membrane layer and decreases the bonding strength of grains, and thus results in brittle fracture. Therefore, controlling the distribution and forms of interstitial impurity elements (C, N, O), and strengthening grain boundaries become key points of improving mechanical properties of tungsten.?Therefore, in this project, the W-Zr-Ti-C alloys will be synthesized by spark plasma syntering method and/or microwave sintering method, the interaction between micro-alloying elements (Ti, Zr) and interstitial impurity elements (O, C, N), and the effect of micro-alloying on mechanical properties of tungsten and its mechanism would be studied. More specially, the influence of impurities in the grain boundaries on the mechanical properties and the effects of trace Ti, Zr and C on the cleaning and strengthening of grain boundaries will be concerned. The results of this project will provide theoretical and experimental foundation for the development of high-performance tungsten-based materials.